Proximity control for a lavatory



United States Patent 3,505,692 PROXIMITY CONTROL FOR A LAVATORY NormanA. Forbes, Louisville, Ky., assignor to American Standard Inc., NewYork, N.Y., a corporation of Delaware Filed Sept. 18, 1967, Ser. No.668,357 Int. Cl. A47k 1/04 U.S. Cl. 4--166 19 Claims ABSTRACT OF THEDISCLOSURE A proximity control arrangement for a lavatory utilizing adual antenna system for sensing the simultaneous presence of the user infront of the lavatory and the positioning of his hands beneath its waterfaucet. One antenna is disposed in the area beneath the faucet and,after sensing the presence of the users hands, causes the proximitycircuit arrangement to turn the water on and to simultaneously switch toa second antenna, secured along the leading edge of the lavatory, forsensing the presence of the user. When the user leaves the lavatory, theproximity circuit arrangement interrupts the water flow; and after apredetermined delay during which the lavatory surfaces drain dry, thecircuit switches the apparatus back to sensing with the first antenna inreadiness for the next cycle of operation.

The present invention relates to a proximity control system andapparatus for use with a lavatory or other plumbing equipment.

More specifically, the pre ent invention relates to an improvedproximity sensing control arrangement for use with a lavatory utilizinga dual antenna system for sensing the presence of a user andautomatically operating the lavatory.

Most conventional lavatories include one or more fluid valves which areturned on manually by the user who operates the valving device. In manylavatories in public places, valving devices are often spring-loaded andmust be manually held in the on position in order that the water supplycontinue to flow from the spout. These valving devices do not permit theuser the freedom to employ both of his hands simultaneously in washingthem beneath the spout. In lavatories located in industrial andcommercial areas, the valving devices often become contaminated withdirt, grease or ink while manually operated by the user to wash hishands.

In an attempt to overcome these disadvantages, lavatories have beenprovided with proximity sensing circuits which are responsive to thehands of the user being inserted beneath the lavatory spout. Theselavatories generally utilize a single antenna sensing device which ispositioned in an area beneath the water spout and designed to detect thepresence of the users hands. After the water is turned on, however, theantenna may be said to have difficulty in distinguishing between thepresence of the water in the basin flowing from the spout and the usershands. The water will thus continue to flow from the spout of thelavatory even after the user removes his hands from the basin of thelavatory. In attempts to overcome these ditficulties, a proximityantenna has been mounted on the front or leading edge of the lavatoryaway from the basin and water supply. Such a lavatory, however, suffersfrom the disadvantage in that persons who merely pass in front of thelavatory or stand or sway in front to adjust themselves before a .mirrorabove the lavatory, often turn the water upply on and thus cause anunnecessary wastage of water.

Accordingly, the present invention overcome all of the above mentioneddifiiculties by providing an improved ice proximity sen-sing lavatoryhaving a high reliability dual sensing antenna system. The novellavatory utilizes a first sensing antenna which may be positionedbeneath the outlet of the water spout behind the basin of the lavatory.The second antenna may be positioned along the leading edge of thelavatory as, for example, in front of its basin. The second antenna,however, remains normally disconnected from the proximity sensingcircuit until the user places his hands beneath the water faucet in thevicinity of the first antenna. The first antenna is geared to equipmentwhich will then cause the proximity sensing circuit to operate asolenoid valve to permit the water to flow from the spout. The proximitycircuit will also be geared so as to simultaneously disconnect the firstantenna from its input and connect itself to the second antennapositioned at or in the region of the leading edge of the lavatory. Thewater will continue to flow from the faucet until the user withdrawsfrom the lavatory and is out of the range of the second antenna. TheWater flowing in the basin will not affect the proximity sensing circuitsince the first antenna has been disconnected from the circuit from thetime the water started to flow. After the water from the faucet stopsflowing, the proximity sensing circuit arrangement will operate todisconnect the second antenna and reconnect the first antenna to itsinput in readiness for another cycle of operation.

It is therefore an object according to the present invention to providean improved proximity control arrangement for use with a lavatory havinga dual antenna sensing system responsive to the approach and withdrawalof the user.

It is a further object according to the present invention to provide aproximity control for use with a lavatory which conserves water byoperating only when required by the user.

It is another object according to the present invention to provide aproximity control which is simple in design, easy to manufacture andreliable in operation.

Other objects and features of the present invention will become apparentfrom the following detailed description considered in connection withthe accompanying drawings which disclose certain embodiments of thepresent invention. It should be understood, however, that the drawingsare designed for the purpose of illustration only and not as adefinition of the limits of the invention as to which reference shouldbe made to the appended claims.

In the drawings wherein similar reference characters denote similarelements throughout the several views:

FIG. 1 illustrates the placement of the dual antennas of the proximitycontrol system according to the invention within a lavatory; and

FIG. 2 is a schematic representation, partially in block diagram, of thecontrol circuit of FIG. 1.

Referring to FIG. 1 there is shown a lavatory 10 having a spout 13disposed over basin 14. A drain 15 is provided at the lowest pointwithin basin 14, preferably beneath the opening of faucet 13 as shown.Secured behind basin 14, along its vertical wall beneath faucet 13, is afirst sensing antenna 11, shown in dotted lines. Antenna 11 also includea wire shield 12 surrounding it and secured against the inside wall ofthe basin. Lavatory 10 also includes a second sensing antenna 21, alsoshown in dotted lines, secured beneath and behind the leading edge ofthe lavatory in front of basin 14. Antenna 21 also includes a wireshield 22 surrounding it and secured to the leading edge. Both antennasand their shields may, of course, be concealed within or under thelavatory.

Referring to FIG. 2., there is shown, partly in schematic form, theconnection of the antennas 11 and 21 to a proximity sensing circuit 16capable of detecting antenna capacitance changes. The proximity sensingcircuit is of a type that provides a shield or guard terminal which canbe used to shield the antenna lead wire from grounded objects. Such aguard circuit is commonly used in sensitive capacitance measurements,and is well known to the art of instrumentation. In such proximitysensing circuits, the shield or guard is not grounded, and objectsconnected to the shield or guard have negligible effect on the antenna.Apart from the shield or guard terminal, the proximity sensing circuitis one serving merely to respond to changes in capacity to operate atranslating device or other apparatus.

Coupled to the output of sensing circuit 16 is a relay 19 having a coil40 and a contact arm 44. In the de-energized state of relay 19 (asshown), contact arm 44 is disconnected from contact 39. Line powersource 18 is connected permanently to the primary winding P oftransformer 26. The secondary winding S of transformer 26 is coupled toa conventional full-wave rectifying bridge 25. In addition, a capacitor24, connected across the D-C terminals of bridge 25, serves as a filterfor the rectified current applied to relay coils 20 and 30 of relays 60and 70, respectively.

While the circuit of FIG. 2 remains in a de-energized state, i.e., inthe condition shown in FIG. 2, the primary winding P of transformer 36is connected to the contact arm 39 of relay 19, this relay remainingde-energized. Hence, substantially no voltage will be applied by thesecondary winding S of transformer 26 to the base-emitter terminals oftransistor 52 over the half-wave rectifierfilter circuit which includesrectifier 35, bleeder resistor 33 and capacitor 34. Thus, the baseterminal of transistor 52 will draw essentially no current. Whiletransistor 52 remains non-conducting, this condition does not interferewith the conductivity of transistor 53, the base electrode of which canreceive current flowing through resistor 55 and hence transistor 53draws appreciable current at this time. When transistor 52 becomesconductive later in the cycle, the junction of resistor 55 and thecollector of transistor 52 are essentially connected to the emitter oftransistor 53, and the base current of transistor 53 falls to a very lowvalue so that transistor 53 essentially becomes non-conducting.

While the circuit of FIG. 2 continues to remain in a deenergized statewith an appreciable current flowing to the base electrode of transistor53, the winding 20 of relay 60 will be energized by the fioW of currentsupplied from transformer 26 over the circuit of rectifier 25, thewinding 20 of relay 60, the collector-emitter electrodes of transistor53 and back through rectifier 25. When the armature 27 of relay 60 isclosed against its contact 28, the antenna 11 will be connected to theinput terminal 43 of the proximity sensing circuit 16. Hence, theantenna 11 will be ready to respond to a significant change incapacitance arising from a user placing his hands in the vicinity of thefaucet 13. The winding 30 of relay 70, which is connected to thetransformer 26 and rectifier by a circuit which is parallel to thewinding 20 of relay 60, will not be energized by its connection to thecollector-emitter circuit of transistor 52 due to the absence ofappreciable current flowing to the base of transistor 52. Relay 70 willtherefore remain released. Hence, antenna 21 will remain disconnectedfrom the input terminal 43 3f the proximity sensing circuit 16 becauseof the dis- :onnection of the armature 37 from its contact 38.

The relay coils 20 and may be of any well known :ype, but they arepreferably parts of reed relays having :ontacts which are suitable forswitching very small currents. Capacitors 50, 51, 56 and 57 are employedfor :ransient voltage suppression.

It will be apparent that, after antenna 11 responds to he presence ofpart of a users body, the proximity cir- :uit 16 will cause relay 19 tooperate. The closure of the :ontact 39 will connect the AC. voltagesource 18 to ransformer 36. Rectified current will now flow through theabove-noted rectifier-filter circuit, which includes rectifier 35, tothe base-emitter circuit of transistor 52, thereby rendering transistor52 conducting. Relay 70 will now operate and connect the antenna 21 tothe input terminal 43 of the proximity circuit 16 via the armature 37and contact 38 of relay 70.

The circuit of FIG. 2 operates as follows:

When the user approaches lavatory 10 and places his hands in thevicinity beneath faucet 13, the presence of his hands is sensed by thechange in capacitance between antenna 11 and ground, causing proximitycircuit 16, which is connected thereto via the armature 27 and contact28 of relay 60, to operate. This energizes relay 19 and solenoid valve17. As is well known, solenoid valve 17 is connected to and controls thewater pipeline connection that feeds faucet 13 so that water will beginto flow into the basin of the lavatory. Any type of solenoid valve willbe appropriate for this arrangement of this invention. Contact arm 44 ofrelay 19 will close its contact 39 and cause coil 30 of relay 70 to beenergized by means of transistor 52 over the network connectingtransformer 36 to relay coil 30. Antenna 21 will now be connected to theinput terminal 43 of proximity circuit 16. Simultaneously, transistor 53will ceas e conducting and thus will de-energize relay coil 20 so thatcontact arm 27 will become disconnected from contact 28. Antenna 21will. continue to sense the presence of the user in front of thelavatory and maintain solenoid valve 17 in an energized condition whilethe user is in proper position. As soon as the user withdraws from therange of antenna 21, proximity sensing circuit 16 will de-energizesolenoid valve 17 and relay coil 40. Hence, antenna 11 will once againbecome connected to the input terminal 43 of proximity circuit 16 inreadiness for the next cycle of operation.

Relays 60 and 70 and their associated circuitry and contacts may becontained within a shielded mounting 42 shown in dotted lines andsecured in an accessible position in a chamber or other location beneathor adjacent to lavatory 10. Shielded case 42 is connected at terminal 41to both shields 12 and 22 surrounding or supporting the antennas. Theseconnections may be conveniently performed by utilizing shielded coaxialcables having insulated center conductors connected from terminals 45and 46 to antennas 11 and 21, respectively.

In an actual embodiment of the present invention, lavatory 10 wasconstructed from non-conducting material so that both antennas 11 and 21would be effective through the walls of basin 14 in sensing proximity.Typical component values were chosen as follows:

Transformers 26 and 36-Primary 120 v., secondary 6 v. Capacitors 50 and510.1 ,uf., 25 v. rating.

Capacitor 24-250 ,uf., 50 v. rating Capacitor 3450 ,uf., 10 v. ratingCapacitors 56 and 57-0.01 ,uf., 25 v. rating Relay coils 20 and 30-300ohm coils Power source 1812O v. AC, 60 cycles Resistor 23-1O ohmsResistors 33, 54-106 ohms Resistor 47,000 ohms In addition, thefollowing capacitance measurements were made at the antennas:

Capacitance of one antenna to ground equals 7.9 pf. Capacitance of oneantenna to shield equals 70 pf. Capacitance of shield to ground equals260 pf.

With the above parameters, each antenna could be adjusted to operateproximity circuit 16 by moving the hand to a distance of approximately5-6 inches from the antenna.

From the above measurements, it should be noted that by isolatingantenna relays and and the shields of the antennas from ground, theelectronic hardware mounted close to the antenna will have negligibleeffect upon the sensitivity of the proximity circuit so long as theshields are between the antennas and grounded hardware. It can beappreciated that if the antenna shields were directly connected to theground, the sensitivity of the proximity circuit would be greatlyreduced.

Thus, the antenna 11 responds to the positioning of the users handsunder or within short range of the faucet 13. The proximity circuit 16,under the control of antenna 11, turns on the solenoid valve 17 and,almost simultaneously, disconnects antenna 11 from the sensing circuit16. The proximity circuit 16 substitutes antenna 21 in place of antenna11. Antenna 21 will continue to hold the sensing circuit 16 activateduntil the user leaves the scene of the lavatory 14. When this happens,antenna 21 will be disconnected from sensing circuit 16 and replaced byantenna 11. This restores the status quo for another cyclical sequence.

Shielded case 42, and the outer conductors of the co axial cablesconnected to shielded case 42, must be connected to the guard terminalmentioned formerly, so that the switching described above can beaccomplished without introducing additional capacitance from antenna 11to ground or from antenna 21 to ground. The purpose of isolatingtransformers 26 and 36 is to keep the impedance from shielded case 42 toground at a high level. In the example of FIG. 2, this shield-to-groundimpedance is essentially the primary-to-secondary interwindingcapacitance of transformers 26 and 36.

The arrangement of this invention may obviously be employed to controlthe operation of the faucet 13 with any number of antenna or capacitycombinations, such as 11, 12 and 21, 22. The mechanism may be adjustedto cause the various capacitor combinations to respond to the proximityof different parts of the users body. Unless all capacitances reachedpredetermined values, the faucet 13 would fail to operate. And thefaucet 13 would continue to operate while any one of said capacitancesmaintained its predetermined value. But when the charge on the lattercapacitance receded from its predetermined value, the operation of thefaucet 13 would be stopped.

While only certain embodiments of the present invention have been shownand described merely for the purpose of illustration, it will beunderstood that many changes and modifications may be made thereuntowithout departing from the spirit and scope of the invention.

What is claimed is:

1. The combination of a faucet, a plurality of antennas respectivelyadapted to be exposed to different parts of a users body, each adaptedto change in capacitance by a predetermined amount only when therespective part of the users body is in close proximity to said faucet,and means to operate said faucet only when all of the respectiveantennas are changed in capacitances to predetermined values.

2. The combination according to claim 1 including, in addition, means torelease said faucet when the capacitances of said antennas fall belowtheir respective predetermined values.

3. The combination according to claim 1, in which the faucet operatingmeans includes a solenoid valve.

4. The combination of a faucet, a first antenna positioned so as torespond to the proximity of one part of a users body relative to theposition of the faucet, a second antenna positioned so as to respond tothe proximity of another part of the users body relative to the faucet,means responsive to a predetermined change of said first antenna tooperate said faucet, means to maintain the faucet operated for apredetermined time interval and to render the faucet operating meansnon-responsive to said first antenna, means responsive to apredetermined change of said second antenna to continue said faucetoperated until the change of said second antenna is reduced below thelatter predetermined change.

5. A combination in accordance with claim 4 in which the faucetoperating means includes a proximity sensing ClIClllt.

6. A combination according to claim 5 in which the faucet operatingmeans also includes a solenoid valve.

7. An arrangement for the control of a faucet, comprising two antennaspositioned on opposite sides relative to the outlet of said faucet, oneof said antennas responding by changes in its capacitance when one partof a users body is in close proximity thereto, and the other antennaresponding to changes in its capacitance when another part of a usersbody is in close proximity thereto, means to operate said faucet whenboth antennas respond by predetermined changes in capacitance, and meansto release the faucet operating means to prevent the flow of fluid fromsaid faucet when both antennas have failed to respond by predeterminedchanges in capacitance simultaneously to the proximity of both parts ofthe users body.

8. An arrangement in accordance with claim 7 in which said faucetoperating means includes a proximity sensing circuit.

9. An arrangement in accordance with claim 7 in which said faucetoperating means includes a solenoid valve.

10. The method of controlling the operation of a faucet the flow path ofwhich is positioned between first and second control elements, whichconsists in operating the faucet only when a users hand becomespositioned close to said first element, maintaining the faucet operatedas long as the users body is positioned close to the second element evenwhile the users hand becomes more widely spaced from the first element,and closing said faucet when the users body becomes more widely spacedfrom the second element.

11. A proximity control for use with a lavatory for providing anautomatic flow of a liquid from its faucet in response to the presenceof a user comprising:

a proximity sensing circuit,

valve means coupled to said circuit for controlling the flow of saidliquid, and

antenna means coupled to said proximity circuit and disposed within thelavatory for sensing the presence of the body of the user in front ofand his hands within the basin of the lavatory.

12. The control as recited in claim 11 wherein said antenna meanscomprises:

a first antenna normally coupled to said proximity circuit for sensingthe presence of the hands of the user within the lavatory basin,

a second antenna for sensing the presence of the user in front of thelavatory, and

means responsive to said first antenna for energizing said secondantenna and said valve means and deenergizing said first antenna.

13. The control as recited in claim 12 wherein said first antenna isdisposed beneath the faucet and behind the basin wall of the lavatory.

14. The control as recited in claim 13 wherein said second antenna issecured in front of said basin along the leading edge of said lavatory.

15. The control as recited in claim 14 wherein said means for energizingcomprises:

switch means coupled to said proximity circuit and responsive to saidfirst antenna for connecting said second antenna to said proximitycircuit and disconnecting said first antenna from said circuit.

16. The control as recited in claim 15 wherein said switch meanscomprises:

a first normally-closed relay for coupling said first antenna to saidproximity circuit,

a second normally-open relay for coupling said second antenna to saidproximity circuit, and

a master relay responsive to said proximity circuit for opening saidfirst relay, closing said second relay, and operating said valce meansin response to the presence of the user within the basin of thelavatory;

a 7 8 and, opening said second relay, closing said first relayReferences Cited and turning ofi? said liquid when the user withdrawsfrom the proximity of said second antenna. UNITED T T PATENTS 17. Thecontrol as recited in claim 16 wherein said 3,033,248 5/ 1962 Rltchle22276 XR valving means comprises at least one solenoid valve for3,151,340 10/1964 Teshlma 4-466 5 3,415,278 12/1968 Yamarnoto et a1.4166 controlling the flow of liquid from said faucet.

18. The control as recited in claim 17 wherein said first and secondantennas are electrically isolated from ground MERVIN STEIN PnmaryExammer G. H. KRIZMANICH, Assistant Examiner potential.

19. The control as recited in claim 18 wherein said first US. Cl. X.R.

and second antenna relays are isolated from ground 10 potential. 22252;251132

